scholarly journals The extensibility of the plantar fascia influences the windlass mechanism during human running

2021 ◽  
Vol 288 (1943) ◽  
pp. 20202095
Author(s):  
Lauren Welte ◽  
Luke A. Kelly ◽  
Sarah E. Kessler ◽  
Daniel E. Lieberman ◽  
Susan E. D'Andrea ◽  
...  

The arch of the human foot is unique among hominins as it is compliant at ground contact but sufficiently stiff to enable push-off. These behaviours are partly facilitated by the ligamentous plantar fascia whose role is central to two mechanisms. The ideal windlass mechanism assumes that the plantar fascia has a nearly constant length to directly couple toe dorsiflexion with a change in arch shape. However, the plantar fascia also stretches and then shortens throughout gait as the arch-spring stores and releases elastic energy. We aimed to understand how the extensible plantar fascia could behave as an ideal windlass when it has been shown to strain throughout gait, potentially compromising the one-to-one coupling between toe arc length and arch length. We measured foot bone motion and plantar fascia elongation using high-speed X-ray during running. We discovered that toe plantarflexion delays plantar fascia stretching at foot strike, which probably modifies the distribution of the load through other arch tissues. Through a pure windlass effect in propulsion, a quasi-isometric plantar fascia's shortening is delayed to later in stance. The plantar fascia then shortens concurrently to the windlass mechanism, likely enhancing arch recoil at push-off.

2016 ◽  
Vol 1136 ◽  
pp. 520-525
Author(s):  
Hiromi Isobe ◽  
Keisuke Hara

This paper reports the stress distribution inside the workpiece under ultrasonic vibration cutting (UVC) condition. Many researchers have reported the improvements of tool wear, burr generation and surface integrity by reduction of time-averaged cutting force under UVC condition. However general dynamometers have an insufficient frequency band to observe the ultrasonically varying processing phenomena induced by UVC. In this paper, stress distribution inside the workpiece was observed by combining the pulse laser as light source synchronized with ultrasonically vibrating cutting tool and the photoelastic method. The one shot of pulse laser with pulse width of 15nsec visualizes an instantaneous stress distribution. Sweeping the phase of emission against to ultrasonic oscillation, 360 frames for 35.7μs, one period of ultrasonic oscillation, are captured. Because UVC induced an intermittent cutting condition, the stress distribution changed periodically and disappeared when the tool leaved from the workpiece. The ideal chip-generating period is calculated by relative motion between tool and work. We found that the actual chip-generating period was extremely longer than ideal period.


2020 ◽  
Vol 20 (3) ◽  
pp. 298-313
Author(s):  
Matthias Gross

The German Autobahn has inspired many people’s imagination with its lack of a general speed limit, the quality of its road surface as well as its allegedly well-behaved drivers. One of the consequences of this positive reputation has been the emergence of a phenomenon I would like to call “speed tourism.” In this article, I treat speed tourism as a special form of tourism that involves viewing the driving experience as an opportunity for either testing the capacity of one’s own car or driving it at high speed as a way of experiencing the native culture at firsthand. I explore speed tourism as an alternative way of getting to know the real Germany as a tourist. Based on an analysis of several of its peculiarities, I argue that the Autobahn can be understood as a location where tourists can mix with “locals” while keeping a distance from them, since the interaction is restricted to learning and obeying the country’s rules of the road. The Autobahn then becomes a time-bound “dream location” created by the ideal of limitless driving freedom on the one hand and the paradoxical requirement of unruliness in relation to strict rules on the other; together, these are believed to offer an “authentic” driving experience according to local cultural customs.


Author(s):  
Michael P. Lynch

This chapter argues that academic freedom is justified because it is an inherently epistemic practice that serves the ideals of democracy. With Dewey, it is argued that “The one thing that is inherent and essential [to the idea of a university] is the ideal of truth.” But far from being apolitical, the value of pursuing truth and knowledge—the value that justifies academic freedom, both within and without the public mind—is a fundamental democratic value, and for three reasons: the practices of academic inquiry exemplify rational inquiry of the kind needed for democratic deliberation; those practices serve to train students to pursue that kind of inquiry; and those practices are important engines of democratic dissent.


2021 ◽  
Vol 37 (01) ◽  
pp. 045-052
Author(s):  
Mario Bazanelli Junqueira Ferraz ◽  
Guilherme Constante Preis Sella

AbstractNasal dorsal preservation surgery was described more than 100 years ago, but recently has gained prominence. Our objective is to show the surgical technique, the main indications and counterindications, and the complications. It is a technique that does not cause the detachment of the upper lateral cartilage (ULC) from the nasal septum, and has the main following sequence: preparation of the septum and its resection can be at different levels (high or low, i.e., SPAR [septum pyramidal adjustment and repositioning] A or B); preparation of the pyramid; transversal osteotomy; lateral osteotomy(s); and septopyramidal adjustment. The result is a nose with a lower radix than the original, a deprojection of the nasal dorsum tending to maintain its original shape; an increase in the interalar distance (IAD) and enlargement of the nasal middle ⅓; and loss of projection of the nasal tip and roundness of the nostrils. Thus, the ideal candidate is the one who benefits from such side effects, that is: tension nose, that is, high radix with projected dorsum, projected anterior nasal septal angle (ANSA), narrow middle ⅓, narrow IAD, thin nostrils and straight perpendicular plate of the ethmoid (PPE), and, depending on the characteristics, the deviated nose. The counterindications are low radix, irregularities in the nasal dorsum, ANSA lower than rhinion, and a wide middle ⅓. And the main stigmas are: a nose with a very low radix, middle ⅓ enlarged, residual hump, and saddling of the supratip area. Other issues of this technique are: the shape of the radix; the need or not to remove PPE; wide dorsum; irregular dorsum; ANSA lower than rhinion; weak cartilages; long nasal bone; deviated PPE; and obsessive patient. We conclude that this is a great technique for noses with characteristics suitable to it; care must be taken with the stigmas it can cause.


2008 ◽  
Vol 10 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Roch Plewik ◽  
Piotr Synowiec ◽  
Janusz Wójcik

Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe The hydrodynamics in fluidized-bed crystallizers is studied by CFD method. The simulations were performed by a commercial packet of computational fluid dynamics Fluent 6.x. For the one-phase modelling (15), a standard k-ε model was applied. In the case of the two-phase flows the Eulerian multi-phase model with a standard k-ε method, aided by the k-ε dispersed model for viscosity, has been used respectively. The collected data put a new light on the suspension flow behaviour in the annular zone of the fluidised bed crystallizer. From the presented here CFD simulations, it clearly issues that the real hydraulic conditions in the fluidised bed crystallizers are far from the ideal ones.


Author(s):  
Zijian Guo ◽  
Tanghong Liu ◽  
Wenhui Li ◽  
Yutao Xia

The present work focuses on the aerodynamic problems resulting from a high-speed train (HST) passing through a tunnel. Numerical simulations were employed to obtain the numerical results, and they were verified by a moving-model test. Two responses, [Formula: see text] (coefficient of the peak-to-peak pressure of a single fluctuation) and[Formula: see text] (pressure value of micro-pressure wave), were studied with regard to the three building parameters of the portal-hat buffer structure of the tunnel entrance and exit. The MOPSO (multi-objective particle swarm optimization) method was employed to solve the optimization problem in order to find the minimum [Formula: see text] and[Formula: see text]. Results showed that the effects of the three design parameters on [Formula: see text] were not monotonous, and the influences of[Formula: see text] (the oblique angle of the portal) and [Formula: see text] (the height of the hat structure) were more significant than that of[Formula: see text] (the angle between the vertical line of the portal and the hat). Monotonically decreasing responses were found in [Formula: see text] for [Formula: see text] and[Formula: see text]. The Pareto front of [Formula: see text] and[Formula: see text]was obtained. The ideal single-objective optimums for each response located at the ends of the Pareto front had values of 1.0560 for [Formula: see text] and 101.8 Pa for[Formula: see text].


2005 ◽  
Vol 7 (2) ◽  
pp. 139-163 ◽  
Author(s):  
Richard L. Venezky

Philologists, linguists, and educators have insisted for several centuries that the ideal orthography has a one-to-one correspondence between grapheme and phoneme. Others, however, have suggested deviations for such functions as distinguishing homophones, displaying popular alternative spellings, and retaining morpheme identity. If, indeed, the one-to-one ideal were accepted, the International Phonetic Alphabet should become the orthographic standard for all enlightened nations, yet the failure of even a single country to adopt it for practical writing suggests that other factors besides phonology are considered important for a writing system. Whatever the ideal orthography might be, the practical writing systems adopted upon this earth reflect linguistic, psychological, and cultural considerations. Knowingly or unknowingly, countries have adopted orthographies that favour either the early stages of learning to read or the advanced stages, that is, the experienced reader. The more a system tends towards a one-to-one relationship between graphemes and phonemes, the more it assists the new reader and the non-speaker of the language while the more it marks etymology and morphology, the more it favours the experienced reader. The study of psychological processing in reading demonstrates that human capacities for processing print are so powerful that complex patterns and irregularities pose only a small challenge. Orthographic regularity is extracted from lexical input and used to recognise words during reading. To understand how such a system develops, researchers should draw on the general mechanisms of perceptual learning.


2020 ◽  
Vol 36 (2) ◽  
pp. 249-277
Author(s):  
Tzu-Lung Chiu
Keyword(s):  
The One ◽  

Vinaya rules embody the ideal of how Buddhists should regulate their daily lives, and monastics are required to observe them, despite the fact that they were compiled nearly 2,500 years ago in India: a context dramatically different not only from Chinese Buddhism's present monastic conditions, but from its historical conditions. Against this backdrop, rules of purity (qinggui) were gradually formulated by Chinese masters in medieval times to supplement and adapt vinaya rules to China's cultural ethos and to specific local Chinese contexts. This study explores how the traditional qinggui are applied by the Buddhist sa?gha in present-day Taiwan, and contrasts modern monastics' opinions on these rules and their relation to early Buddhist vinaya, on the one hand, against classical Chan literature (such as Chanyuan qinggui) and the Buddhist canon (such as Dharmaguptakavinaya), on the other. This comparison fills a notable gap in the existing literature.


Author(s):  
Ainhoa LASA LÓPEZ

LABURPENA: Artikulu honetan, Europar Batasuneko botere-artikulazio berriak erkidegotan osatutako Espainian zer eragin daukan aztertuko dugu. Europa mailako politika-ekonomia erlazioak funtsezko bi koordenatu izan behar ditu ezinbestean. Alde batetik, Europako konstituzio-ordena ez dela gizartearen konstituzionalismoaren koordenatuetan ernatutako ordenaren berdina. Bestetik, Europako konstituzio ekonomikoa Europa bat egiteko proiektuak berarekin dakartzan aldaketa berriak gorpuzteko eremua dela. Izan ere, funtsean, Europako konstituzio ekonomikoa plataforma ezin hobea delako boterearen artikulazioa berria nola artikulatu asmatzeko, Europa guztirako. RESUMEN: el objetivo de este artículo es analizar el impacto que tiene la nueva articulación del poder en la Unión Europea en el Estado español de las autonomías. La relación política-economía a nivel europeo debe tener en cuenta dos coordenadas fundamentales. Por una parte, la consideración del orden constitucional europeo como un orden distinto al gestado bajo las coordenadas del constitucionalismo social. Por otra, la caracterización de la constitución económica europea como ámbito de materialización de las nuevas transformaciones que incorpora el proyecto de integración europeo. Fundamentalmente, porque la constitución económica europea representa la plataforma idónea desde la que dilucidar la nueva articulación del poder desde el espacio supranacional europeo. ABSTRACT: The aim of this paper is to analyse the impact of the new articula tion of power in the European Union in the Spanish state of autonomies. The relationship between politics and economy at European level must take into consideration two fundamental coordinates. On the one hand, the Euro pean constitucional system appears as a system opposite to that of social constitutionalism. Moreover, the characterization of the European economic constitution as a field of realization of the new transformations incorporated by the European project. Specially, because this represents the ideal platform in order to analyse the new articulation of power from European supranational space.


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